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NFL conference finals storylines: Can Bill Belichick deliver again?

For the second consecutive year, Joe Flacco will go up against Tom Brady with a Super Bowl berth on the line. (Al Bello/Getty Images)

Bill Belichick haters gleefully will point to the Patriots' string of recent playoff disappointments as evidence that the crafty ball coach has lost a step. It has been eight seasons, after all, since New England won a Super Bowl (its third in four years), and twice Belichick's team has fallen to the Giants with the Vince Lombardi Trophy on the line.

Still, few coaches have been better in the conference finals -- and the other three teams taking the field this weekend would love to replicate Belichick's success.

The Patriots have reached the AFC title game six times under Belichick's watch. They've won in five of those trips, the lone setback coming in a thriller against the Colts during the 2006 season.

Contrast that 5-1 mark to the rest of the coaches participating Sunday. The Harbaugh brothers are a combined 0-3 in the conference finals, with John losing to Belichick's Patriots one year ago and the Steelers in 2009; and Jim's 49ers gaffing away their chance to the Giants last season. Mike Smith, meanwhile, has never reached this playoff depth as the Falcons' head coach.

How much of an edge does Belichick's past triumphs give New England this week (and, possibly, at the Super Bowl) over a coaching field that has never made it beyond the conference finals?

That's just one of the storylines in the forefront as the NFL crowns its conference champions. Here are a few other subplots to track:

• Making the leap to "elite" levels

SI's Peter King wrote this week that Joe Flacco has claimed in the upper echelon of NFL quarterbacks. There are plenty of football fans out there, though, that could use a little more convincing.

It's hard to argue with Flacco's performance thus far in the playoffs -- Baltimore's QB has posted a 613 yards, five touchdowns, zero interceptions and a 120.0 passer rating, while taking down Andrew Luck and Peyton Manning in back-to-back weekends.

But he has been here, to this conference-finals stage, before. Twice, actually. Both times, he and his Ravens fell short.

Flacco and Atlanta quarterback Matt Ryan have followed similar career arcs. Ryan was the No. 3 pick in the 2008 draft; Flacco came off the board 15 selections later. Since then, Ryan has accumulated the statistics to join the "elite QB" discussion, culminating with a 2012 regular season in which he threw for 4,719 yards, 32 touchdowns and led the league with a 68.6 completion percentage.

Like Flacco, however, Ryan has not been able to get Atlanta over the top. It took until last week, in fact, for the Falcons to finally secure a playoff victory under Ryan's watch, and he will make his NFC championship debut on Sunday.

A Ravens-Falcons Super Bowl would silence just about all the critics of Flacco and Ryan. Can they deliver that matchup?

Kaepernick delivered a record-setting performance in the divisional round, rushing for 181 yards and two touchdowns, plus throwing for 263 yards and another pair of scores, as the 49ers dismantled Green Bay's defense.

Atlanta's D has been stingier than the Packers this season, especially at home, but Russell Wilson still found room to run for 60 yards and a score last week.

The key to the NFC title game, then, might be how well Atlanta can keep Kaepernick in the pocket. The 49ers' young QB is dangerous enough throwing the ball -- add in open lanes to run, and there may be no stopping the San Francisco offense.

Gonzalez said earlier that he was 95-percent sure that he would retire at the end of the season. This week, he bumped that number up to 97 percent.

As plenty of people have speculated, it appears that a Falcons Super Bowl win (or, at the very least, a Super Bowl appearance) could give Gonzalez a feather in his career cap and nudge him into the sunset.

Here's the thing, though: Gonzalez is still really, really good.

He proved that again last week against Seattle, hauling in six catches, including a tip-toeing touchdown in the back of the end zone. Gonzalez will no doubt be a key figure again as the Falcons try to solve San Francisco.

An Atlanta win might allow Gonzalez to say farewell to his home fans in triumphant fashion. No one would complain one bit if he opted to come back for one more year instead.

• And as for Ray Lewis ...

That other retirement tour just keeps on adding stops.

Lewis informed the Ravens prior to the playoffs that this was his "last ride." Whether or not that extra tidbit of motivation has helped carry the Ravens through the wild-card and divisional rounds, it no doubt has to be in the minds of Lewis' teammates.

The future Hall of Famer has played a key role in the past against Tom Brady (more on that here). He will need to be at his best for the Ravens to get through this week. If that happens, get ready to enter Ray Lewis overload in the two weeks prior to the Super Bowl.

The Patriots finally got their hulking tight end back for Week 17, only to see him leave their win over Houston after suffering another fracture in his troublesome left arm.

The media spent much of Super Bowl week last year on Gronk Watch, to see if Gronkowski could play through an ankle injury. There will be no such mystery this playoff season -- the Patriots placed Gronkowski on injured reserve a couple of days ago.

His absence opens a huge hole in the Patriots' offense. Aaron Hernandez will take on an even bigger role as a weapon for Tom Brady, but New England actually countered Gronkowski's injury last week by getting the ball to its running backs (especially Shane Vereen) more.

Belichick has had a week to figure out his Plan B with Gronkowski out of the lineup. Given Brady's past struggles against the Ravens, that's one more headache neither he nor Belichick really needed.

• How much does the past matter?

The coaching legacy discussion above put this topic on the table, but there are other historical elements at play this weekend.

To wit: The Falcons have won four straight against the 49ers, plus beat San Francisco in the team's only previous playoff meeting (Jan. 9, 1999). Matt Ryan has a 2-0 record versus San Francisco, too.

Of course, none of those matchups came with Jim Harbaugh coaching the 49ers, and Atlanta has yet to see Colin Kaepernick first-hand. Ryan may still draw a little confidence from his past successes against San Francisco, even if they don't mean a whole lot right now.

Brady has to hope the past does not matter much, either. He has played some of the worst football of his career against Baltimore, including a zero-passing TD, two-interception performance in last season's AFC title game.

One of the bright spots for the Texans last week was the spark provided by Danieal Manning in the return game. Manning averaged 54 yards on four kickoff returns, a mark that was buoyed by a 94-yard scamper to open the contest.

The Ravens have to like seeing that tape. They boast one of the league's most lethal return men in Jones, who averaged 30 yards per chance and took two kickoffs back to the house during the regular season. He has the potential to flip the field if New England gives him the opportunity.